Motor brush assemblage



March 26, 1940.

R. C. SEKYRA MOTOR BRUSH ASSEMBLAGE Filed Oct. 27, 1937 EW l n mlm M i @A m40/vo CHARLES .5f/VRAl Patented Mar. 26, 1940 UNITED STATES PATENT OFFiCE MOTOR BRUSH ASSEMBLAGE Application october 27, 1937, serial No. 171,248`

2 Claims.

The present invention relates generally to electrical brushes, and more particularly to a brush assemblage which embodies means for preventing a brush element per se from being ejected from 5 its supporting casing during the operative use of the assemblage.

An object of the present` invention is to provide a brush assemblage of the brush and casing type, which includes means for preventing the 10 ejection of the brush from the casing during use of the assemblage.

Another object is to provide a brush assemblage which includes a brush element having a groove along a predetermined length of one side, and

1.5 a casing having means for cooperating with the grooved brush to prevent its ejection from the casing in a direction of use.

Another object is to provide a brush assemblage which includes a brush that is non-ejectable in Q use towards the commutator.

Another object is to provide a brush assemblage which includes means for preventing the usual brush ejector spring from expanding against the cominutator.

25 Another object is to provide a brush assemblage 30 Other objects and advantages are apparent from the following description, taken in conjunction with the accompanying drawing, in which:

Fig. 1 is a side view of a brush assemblage including one preferred embodiment of the present 35 invention, the assemblage being shown in operative disposition relative to a comrnutator which is diagrammatically drawn;

Fig. 2 is a side view oi a brush assemblage including one embodiment of the present invention,

4 parts being broken away and parts being shown in section for clarity of illustration;

Fig. 3 is a section on the line 3-3 of Fig. 2, a portion of the brush being shown in plan View for purposes of clarity;

45 Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a perspective view of a brush;

Fig. 6 is a section, taken similarly to Fig. 3, of a modified brush assemblage which includes a modification of the invention shown in Figs l4;

50 and,

Fig. 7 is a section on the line l-l of Fig. 6.

Referring to the drawing more particularly by reference numerals, I0 indicates generally a brush assemblage which includes one preferred embodu iment of the present invention. The brush assemblage l@ includes a brush II, and a casing I2.

The brush il isv a conventional graphite brush including a main elongated body I3 of square cross-section and a reduced extension I4 oi circular cross-section. The body I3 has a concave 5 commutator contacting end I5. In one side of the body i3 there is a longitudinal centrally disposed groove I6 which terminates in a dead end to form a shoulder just short of the reduced extension I4. 10

The casing I2 includes a hollow metal core 28 of square cross-section. One end of the core has an enlargement 2I of circular cross-section which has internal threads 23. At the other end ci the core 20 is an inwardly extending boss IS 15 which is located centrally of and extends inwardly from one side of the core 20. The boss i 5 is of a size to extend into the groove I6 for cooperation therewith.

A cover 24 of Bakelite, or the like, of circular 20 cross-section, surrounds the core 2li. A flat ring 25 having a lead clamp 25 extending radially therefrom which grips a lead 2l is disposed against the free end oi the enlarged portion 2| and the cover 24, and is maintained in position 25 by a casing cap generally designated 33 which comprises a metal plug 3| having an externally threaded extension 32 and a Bakelite cover 33 having a knurled exterior. The cap 3D is screwed into engaging position by the threads of the ex- 3o tension 32 engaging the internal threads 23 of the enlarged portion 2|.

A helical spring 35 is disposed within the hollow core 2E). One end of the helical spring surrounds the extension I4 and abuts the body por- 35 tion i3. The other end of the spring 35 is disposed against the extension 32.

In Figs. 6 and '7 there is shown a `Inodiiied brush assemblage 4B which incorporates a modified form of the present invention. The brush assemblage iii includes a brush AI and a casing 42.

The brush 4I comprises an elongated body i3 of square cross-section and a reduced extension it of circular cross-section. The body 43 in- 45 cludes a commutator contacting end i5 which is concave. A longitudinal centrally disposed groove ISG is formed in one side of the body 43 and dead-ends at a point just short of the extension 44 to form a shoulder.

The casing 42 includes a metal core 43 which is of square cross-section to receive the brush di. rIhe core 48 has external threads 49 at one end and internal threads 5B at the other end. At the end adjacent the threads 49 is an inwardly ex- 55 tending projection l of a configuration 'to extend into the groove 46. A cover 52 of circular cross-section and of Bakelite, or other similar material, surrounds the core i8 throughout its unthreaded extent. An externally knurled internally threaded sleeve` 53 engages the threads i9 and maintains a dat ring against one end of the covering 52. The ring Elli has a radially es;- tending lead clamp 55 which securely engages a lead 5t?.

A cap 53 closes that end of the casing remote from the projection 5l and includes a metal plug Eil and an insulating cover dll. The plug has a reduced annular extension @l having external threads @il Which engage the threads Elli of the core 8. l

A helical spring is disposed within the core 4d. One of the spring E33) encircles the cxtension lil and abuts the body portion i3 of the brush di. The other end of the spring @il presses against a metal plate 645 which is thereby firmly thrust against the extension di of the plug A lead G5 is conductively secured to the brush extension 4liat one end and to the plate 5d at the other end.

@poration The operation or" the novel means for preventing a brush from being ejected' from its casing is simple. Considering the modication shown in Figs. 6 and 7, after the lead 5t has been secured in operative relation to the casing d2 by means of the threaded sleeve 53, the brush lll, having the groove in one side thereof, is inserted into the casing :from the left (Fig. 6), the grooved side being located so that the groove will be .entered by the projection 5l. The helical spring is then disposed about the extension titl, the plate l!! is connected to the brush lead 555, and the cap is screwed home in the usual manner. The brush assemblage will is then ready for use.

When the brush assemblage il is mounted in engaging relation to a commutator the major portion or the brush il will be Within the casing the helical spring 63 being under maximum operative compression. As the end of the brush lil is Worn away through contact with the com".

'atorit is graduallyY pushed from the case by the action or" the helical spring After a period of service, the parts of the brush as semblage lil assume the position shown in Fig. 6, the brush lil, of course, being worn to a much shorterlength than is shown. The projection 5l in iitting into the groove [it and in engaging the rearmost limit of the groove ll, provides a stop and prevents the brush 4l from being completely ejected from the casing 42. The projection 5| and the associated groove 45, therefore, prevent the spring 63 from at any time engaging the commutator $5.

The operation of the modification illustrated in Figs. 1 4 is similar to the above-described operation or the modication shown in Figs. 6 and 7.

The boss lil shown in Figs. l'4 is formed by forcing a portion of one side of the core 2l) inwardly, which may be effected manually or automatically on a machine. This may be done before or after the covering 24 is added. The projection il! shown in Figs. 6 and 7 is formed by forcing a portion of one side of the core 48 into a depending projecting relationship. The project-ion 5i likewise may be formed either manually or by machinery. In the modifications disclosed there are provided simple stop means of similar cross-section which are extremely simple in construction, but which are positive in operation in their cooperative relation with a groove formed in a brush element.

lt is arent that there has been provided a construction forming a part of a brush assemblage which adapted to fulll all of the objects and advantages sought therefor.

It is to be und rstood that the foregoing description and accompanying drawing have given by way of illustration and example and not by Way or limitation, the invention being limited only by the claims which follow.

lil/hat is claimed is:

l. A brush assemblage comprising a casing hav ing an open end, a brush slidably disposed in the casing, means urging said brush from the casing through the open end thereof, a longitudinal groove in said brush terminating short of the iilll extent thereof, and a projection on the casing disposed in said groove, whereby the urging means is prevented from completely ejecting the brush from the casing.

2. A brush assemblage comprising casing having an open end, a brush slidably disposed in the casing, means urging said brush from the lcasing through the open end thereof, a longitudinal groove in said brush extending from the end remote from the urging means to just short ci the end adjacent the urging means, and a boss formed on the casing oi` a crosssection and so located to extend into the groove and to abut the dead end of the groove when the brush has been urged into that extreme position to prevent fur ther ejection of the brush.

RAYMOND CHARLES SEKYRA. 

